Success
The transaxle came off the dowels with a loud crack that made me think I had broken the casing or the end of the torque tube flange but all was fine.
Then I turned my attention to the crossmember and having applied a load of heat, I persuaded a 16mm impact socket over the remains of the bolt head and had at it with the impact wrench on a low torque setting and hey presto, out it came
The gearbox mount was next for some attention but I gave the bolts a good dose of deblocker beforehand and they barely put up a fight with the impact wrench. The mount just fell apart upon removal so I feel justified in doing all this.
I forgot to mention that the reversing light switch disassembled itself when I went to disconnect the wiring, so a new one is on order.
I am replacing all the nuts/bolts and washers with new. I was going to give the Bilt Hamber Dyna slip product a try on the fastenings, I’ve been using the aluminium antiseize elsewhere.
I checked the torque tube bearings and there wasn’t a sound from them so I've dodged that bullet
I’’ve found my engine stand, so that will be put into service and have the transaxle bolted on to it which will make cleaning it up a much easier proposition.
I forgot to post up that yesterday, I cleaned up both drive shafts, removing any result and then treating with Bilt Hambers Hydrate 80. Once cured, this was followed by multiple coats of Frosts chassis black and today, they were the treated to multiple coats of stone chip.
I’ve never had any joy with screw extractors- usually caused me more pain than the broken bolt! I used a fire blanket and soldering mat to keep the heat away from the tank as much as possible.